烹饪过程对空心菜和卷心菜硝酸盐潜在安全风险的影响

研究4种烹饪（油炒、汽蒸、微波和水煮）过程对空心菜和卷心菜中硝酸盐、亚硝酸盐和抗氧化能力的影响，并通过抗氧化性/体内亚硝酸盐比（antioxidant/in vivo nitrite ratio,A/N）值评价其硝酸盐潜在安全风险。结果表明，油炒会同时提升叶类蔬菜的硝酸盐含量（28.03%～49.57%）和铁离子还原能力（108.88%～218.35%），而水煮则相反。微波和汽蒸在降低蔬菜硝酸盐含量（31.25%～46.61%）的同时提升铁离子还原能力（76.35%～112.99%）。基于可食用性和A/N值评价结果，在烹饪2 min内空心菜和卷心菜分别选择水煮和油炒烹饪对硝酸盐潜在安全风险的控制效果更好。微波是两种叶类蔬菜相对安全的烹饪方式，但不宜超过4 min，而汽蒸更适宜长时间烹饪（>4 min）。

Effect of Cooking Process on the Potential Safety Risks of Nitrate in Water Spinach and Cabbage

In this study, the effects of four cooking methods (stir-frying, steaming, microwaving and boiling) on the nitrate and nitrite contents and antioxidant capacity of water spinach and cabbage were investigated, and the potential safety risk of nitrate was evaluated by the antioxidant/in vivo nitrite ratio (A/N). The results showed that stir-frying increased the content of nitrate (28.03%?49.57%) and ferric reducing power (108.88%?218.35%) of leafy vegetables, while boiling was the opposite. Microwaving and steaming decreased the content of nitrate (31.25%?46.61%) and increased ferric reducing power (76.35%?112.99%). Based on the edibility and A/N ratio, the potential safety risk of nitrate in water spinach and cabbage cooked for less than two minutes could be controlled using boiling and stir-frying, respectively. Microwaving is a relatively safe way to cook both kinds of leafy vegetables, but should not exceed four minutes, while steaming is more suitable for longer cooking (> 4 min).